The present invention relates to a display apparatus for projecting an image on a screen by means of a light valve element such as a liquid crystal panel and particularly to a projection type image display apparatus such as a liquid crystal projector apparatus and a rear projection type display apparatus.
Heretofore, a projection type image display apparatus such as a liquid crystal projector and a rear projection type display apparatus is known in which light from a light source such as an electric light bulb is intensity-modulated to be changed to shaded light in each pixel in accordance with an image signal by means of light valve means such as a liquid crystal panel, so that an optical image is formed to be projected on a screen in enlarged manner.
In a recent projection type image display apparatus, generally, light from light source means separated into a plurality of colors (e.g. three colors) by spectroscope means is modulated by light valve means corresponding to respective colors (hereinafter, description is made by using a liquid crystal panel instead of light valve means for convenience) and the light having a plurality of color components is then compounded by a compound prism to be projected to the outside of the apparatus by a projection lens and displayed as in image.
At this time, there is provided light guide means for transmitting light from the light source means to the light crystal panel. The light guide means has the function of uniformalizing non-uniform brightness within an illumination range and changing the illumination range to a rectangular illumination range larger than an opening of the rectangular liquid crystal panel. Further, the spectroscope means is provided between the light source means and the liquid crystal panel, and the light guide means and the spectroscope means are mounted to optical holding means together.
At this time, the optical axis from the illumination means to the liquid crystal panel is set wrongly due to manufacturing accuracy of the optical means provided halfway and the optical holding means and the illumination position of the liquid crystal panel is sometimes deviated from the opening range of the liquid crystal panel when the apparatus is simply assembled. Accordingly, the adjustment operation is performed in which the position and the posture of the optical components constituting the light guide means or the spectroscope means are usually adjusted to align the illumination position of the liquid crystal panel with the range sufficiently covering the opening range of the liquid crystal panel.
Heretofore, as prior arts concerning the adjustment of the illumination range of this kind, there are known the structure having an adjustment mechanism of the illumination position as described in, for example, JP-A-2000-2932 and JP-A-2001-264726 and the structure having an adjustment mechanism of the illumination position disposed outside of the apparatus and in which optical components are adhesively fixed after adjustment and the adjustment mechanism is removed as described in JP-A-2003-75696.